Embodiments of the inventive concept relate to analog-to-digital converters (ADCs) and digital-to-analog converters (DACs). More particularly, embodiments of the inventive concept relate to capacitor DAC converting circuits, ADCs including capacitor DAC converting circuits, and semiconductor devices incorporating same.
ADCs are a well known class of circuits that generate corresponding digital data values (or digital code) in response to an applied analog signal. Quite commonly, the generated digital code is correlated to one or more voltage levels of the analog signal, and a sequence of digital codes may be generated for the analog signal over a defined period of time. DACs are also a well known class of circuits that essentially operate to reproduce an analog signal from a corresponding set of digital codes.
There are many different types of ADCs and DACs. ADCs and DACs are used in many applications, and sometimes used in conjunction with one another to facilitate analog signal and digital signal processing. In certain circuits DACs are used within an ADC.
One type of DAC is the so-called capacitor DAC. Capacitor DACs are used in a variety of application such as successive approximation register (SAR) circuits and methods. SAR circuits and methods may be used, for example, to compare data by repeatedly performing digital-to-analog conversion to thereby determine the bit values of the data being compared. While capacitor DACs prove useful in a certain applications, the constituent capacitors are relatively difficult to fabricate within narrow performance tolerances. That is, the constituent capacitors exhibit performance characteristics that vary with fabrication process variations. As a result, circuits incorporating capacitor DACs (e.g., ADC/DAC circuits and SAR circuits) tend to run at relatively low operating speed.